Postulated late Cainozoic high sea levels in the Malay Peninsula

Abstract

Elevated Quaternary shorelines of less than 6m are common and well-established around the coasts of the Malay Peninsula. Quaternary shorelines higher than 6m have been repeatedly postulated, but all such postulations are shown to be based on evidence which is at best inconclusive, in many cases invalid. Several examples of misquotation occur in compilations.

In particular it is shown that:

a) There is no record of in situ marine fossils younger than Triassic, at elevations greater than 6m, in the Malay Peninsula;

b) The elevated Late Cainozoic deposits of Singapore and Peninsular Malaysia, well exposed in open-cast tin mines and gravel pits, show no granulometric or palaeontologic evidence of marine origin; most of the deposits show features indicating fluviatile or colluvial origin;

c) Geomorphic evidence cited for high Quaternary shorelines is scanty and inconclusive;

d) Elevated fluviatile alluvium, and breaks in hill slopes, have been taken as positive evidence of high Quaternary sea levels, without consideration of other possible explanations of these features.

It is concluded that there is no compelling evidence for Quaternary shorelines above 6m, and the balance of evidence is against any eustatic sea levels higher than 6m affecting the Malay Peninsula in the late Cainozoic. It is suggested that future work on the Quaternary will be more fruitful if problems are approached without preconceived ideas about high Quaternary sea levels, and if the evidence is described in detail and evaluated critically.

Summary

This article is a critical review of all postulated Quaternary sea levels exceeding 6 metres in the Malay Peninsula. Haile systematically examines each postulation — from Scrivenor’s early twentieth-century observations through Tjia’s more recent geomorphological interpretations — and demonstrates that the evidence is either invalid, misquoted, or inconclusive. The core argument is that the idea of high eustatic sea levels (30–50 m or more) affecting the peninsula has become entrenched in the literature largely through uncritical citation of Zeuner’s authoritative compilations, which themselves relied on evidence that Scrivenor had already retracted. Haile draws on his own fieldwork examining opencast tin mine sections across West Malaysia, together with aerial photography and topographic maps, to argue that the balance of evidence is against any eustatic sea level above 6 m in the late Cainozoic.

The article also addresses a methodological problem: the tendency of researchers to begin with a preconceived model of world-wide high sea levels (derived from Mediterranean terrace correlations) and then interpret ambiguous local features — breaks in slope, elevated alluvium, cave scalloping — as confirming that model. Haile invokes Gill’s (1967) criteria for Quaternary shoreline description to argue that such features are not in themselves proof of sea-level change, and that the very general nature of descriptions in the existing literature has compounded the confusion.

Key Findings

• No in situ marine fossil younger than Triassic has been recorded at elevations greater than 6 m anywhere in the Malay Peninsula (p. 78).
• The “sponge spicules” from Tanjong Perak Estate, Perak (at ~45 m), originally cited by Scrivenor (1931) as evidence for a +61 m sea level, were shown by Stauffer (1973) to be non-organic glass bubbles and vesicle fragments (p. 81).
• The marine fossils (shell fragments, echinoid spines, doubtful otoliths) found by Burton (1964) in the “Older Alluvium” of Johore and Singapore come from a single locality near the coast, only a few metres above sea level, and do not prove the marine origin of the deposits as a whole (pp. 82–83).
• Tjia’s (1972) ten erosion surfaces on Langkawi limestone, interpreted as sea-level stands between 15 m and 400 m, are shown from aerial photography to be minor breaks in slope on rugged karst terrain, not extensive level surfaces (pp. 79–80).
• The well-established Holocene submergence of ~6 m (dated 5,000–6,000 years BP) is supported by raised beaches, sea caves, and a 3-metre wave-cut notch with attached oysters on limestone coasts, confirmed by radiocarbon dates (Yancey, 1973) (pp. 78–79).
• Zeuner’s (1959) citation of a “+200 feet” Malayan sea level based on Scrivenor’s rhyolite-ash evidence persisted in the literature even after Scrivenor had retracted the interpretation in 1942–1946 (p. 81).

Conclusion

Haile concludes that there is no compelling evidence for Quaternary shorelines above 6 m in Peninsular Malaysia, and that the balance of evidence — particularly the absence of marine fossils in the extensively exposed opencast mine sections — argues against any eustatic sea level higher than 6 m in the late Cainozoic. He urges that future Quaternary research in the region proceed without preconceived assumptions about high sea levels, and that features be described in detail and evaluated critically against established criteria.

Context

• Haile’s argument is grounded in his own fieldwork examining opencast tin mine sections across West Malaysia, aerial photography of the Langkawi Islands, and 1-inch topographic maps, combined with a systematic re-examination of the published literature.
• The article represents a significant historiographical intervention in Quaternary geomorphology of the region, challenging the entrenched narrative of high eustatic sea levels that had been incorporated into the standard reference work The Geology of the Malay Peninsula (Gobbett and Hutchison, eds, 1973).

References